In Multi-Access Networks, different access technologies (ATs) are used to provide an overlay of different accesses (As).
Typically, a data session, which is in the later called a bearer, has certain Quality of Service requirements (QoS), e.g. in terms of required data rate, delay, residual errors, etc.
Multi Access Management (MAM) is a function that observes the performance and capabilities of different accesses (As) that can be used for a bearer, and selects the one—or more in case of parallel usage of multiple links—access (A) which is (best) suited to the bearer requirements.
For this purpose, Multi Access Management (MAM) requires information about the performance and capabilities of the different accesses (As) which are available for the bearer.
Such information by way of example may comprise a rate requirement and/or a delay requirement and/or a (residual) bit error rate and/or a (residual) packet error rate.
One problem is that different accesses (As) use different access technology specific metrics to specify their performance respectively capabilities. A metric is understood as being any kind of information related to a quantification of characteristics.
These technology specific metrics may comprise by way of example, a raw bit error rate and/or a Received Signal Strength Indicators (RSSI) and/or a Signal to Interference-plus-Noise Ratio (SINR).
Therefore, it is difficult to compare the different accesses (As).
For example, it is not trivial to compare a received signal strength indicator (RSSI) of −15 dBm for a WLAN radio access (A) with a 3G radio access (A) with a signal-to-noise-and-interference ratio of 3 dB.
In order to make such a comparison possible, the Generic Link Layer (GLL) provides a functionality to translate access technology specific access characteristics into a generic performance/capability of the access, i.e. an abstraction. As is well known in the art the GLL provides generic data processing for a multitude of radio access technologies.
Based on the generic access capability/performance descriptions provided by the Generic Link Layer entities, a Multi Access Management (MAM) should provide an appropriate access selection decision.
Hence, the Generic Link Layer abstracted access capabilities should be matchable with the QoS requirements of the bearer.
Therefore, the abstractions should be similar to the QoS metrics, like data rate, delay, residual bit error rate (BER) or packet error rate (PER).
One problem is, how this access performance abstraction shall be carried out.
Another problem is, that for one set of access specific performance metrics (ASPM), i.e. the access performance, a plurality of different generic performance metrics (GPM) may be generated, depending on how the link layer is configured. Generic Performance Metrics may include rate, delay, Bit Error Rate (BER) and packet error rate (PER).
Hence, there is typically a set of generic performance metrics (GPM) owing to different possible configurations.
Therefore, it is a problem to decide, which one of the generic performance metrics (GPM) should be used representing a specific configuration of an Access and/or which specific Access should be used.
Known techniques, such as in UMTS-systems, do not experience such problems, since the resources of the system are adapted after they are selected to fulfill the requirements to their best.
However, these techniques are neither flexible nor allow for optimization of fixed amounts of resources.